Is deck cleaner required before oiling deck?

[TimD]

Hi,

   I'm new to decks and thinking of giving ours a refresh. Saw this post How to restore a deck  which was very useful. My question is do I need to use a deck cleaner on my deck as I think the boards are in reasonable condition compared to those listed in projects on this site? The cleaners look quite corrosive and wondering if I will do unnecessary damage to the wood. Could I just need to give it a good clean with a garden hose and then oil?

Do you recommend a particular cleaner (if necessary) and a particular oil?

Pictures below

Section Under CoverMore exposed areaMore Exposed Area

Thanks

Tim

[MitchellMc]

Hi @TimD,

Products like Cabot’s Deck Cleaner are designed specifically for timber and will not damage your boards at all. They break down surface grime, old oils, and weathered fibres so the fresh coat can bond properly, and they are much more effective than a quick hose down. Giving the deck a proper scrub with a cleaner is an important part of getting an even finish, so I would definitely recommend using one.

The undercover section should respond well to a single clean with deck cleaner and then oiling. The exposed section has clearly weathered more and the greying and flaking you are seeing is the old coating breaking down. A cleaner will remove the surface layer, although it will not bring that area back to the same appearance as the undercover boards. If you are happy with the look as it is, you can clean it thoroughly with deck cleaner, scrub the exposed boards with a stiff-bristle brush, let it dry, and then apply your oil. If you want that exterior area to look new again, it would need to be sanded before oiling. 

Here's a helpful guide: How to oil your deck.

Please let me know if you have any questions.

Mitchell

[TimD]

Great, thanks Mitchell for the quick response. I assume I can use a water based oil (I don't know what was used previously) - something like this https://www.bunnings.com.au/cabot-s-4l-merbau-aquadeck-exterior-decking-oil_p1520084 or this https://www.bunnings.com.au/timber-protect-10l-water-based-decking-oil_p1400468 ? or is there something you would particularly recommend?

Thanks

Tim

[MitchellMc]

Typically, I'd recommend a water-based product such as Cabot's 4L Merbau Aquadeck Exterior Decking Oil, @TimD. I suspect a water-based product was used previously, so it's best to keep it the same.

Mitchell

[TimD]

Thanks Mitchell,

Tim

[TimD]

Hi Guys,

    I bought natural oil but later realised that there are 3 types of oil  - Merbau, Jarrah and natural.

I spoke with the previous owner of the house and he thought it might be spotted gum but not 100% sure.

Do you know whether it is Merbau,  Jarrah or spotted gum? I haven’t opened the oil it yet so should be able to exchange if need be or would safest bet be to just use natural?

Before Cleaning

This is how  the deck looks now that I’ve sanded and cleaned a few slats 

 

Thanks

Tim

[MitchellMc]

Hi @TimD,

Natural oil works well when the timber is already in good condition and still holds much of its own natural colour. It nourishes the surface without adding any tint, so whatever colour variation is already present in the boards will remain visible. When the timber has greyed or lost its original richness, a tinted oil such as Merbau or Jarrah is usually the better option because it helps restore depth and even out the appearance.

From the photos and your description, there is a good chance the boards are spotted gum. There is no specific spotted gum tint available in decking oils, so the choice generally comes down to natural or one of the common warm-toned tints like Merbau or Jarrah. Although natural oil should be fine for the undercover section where the timber still looks consistent, the exterior boards are showing quite a bit of patchiness with clear differences in light and dark areas. If you apply natural oil to that section, the uneven colouring will stand out even more. I would suggest that you continue sanding until you've reveiled fresh timer on all the boards.

A Merbau-tinted oil is likely the safest option if you want to bring the exterior boards closer to a uniform tone. 

Mitchell

[TimD]

Thanks again Mitchell,

Regards

Tim